Continuous Chest Compressions During CPR Do Not Enhance Cardiac Arrest Outcomes

Patients experiencing non-trauma–related cardiac arrest derive no added protection against death or neurological damage when emergency medical services (EMS) providers use continuous chest compressions during cardiopulmonary resuscitation (CPR).

The findings were presented at the American Heart Association Scientific Sessions 2015 in Orlando, FL, and simultaneously published online in the New England Journal of Medicine.

Graham Nichol, MD, MPH, of the University of Washington–Harborview Center for Prehospital Emergency Care (Seattle, WA), and colleagues randomized 23,711 patients to chest compression that was continuous with positive-pressure ventilation (n = 12,653) or interrupted for ventilations at a ratio of 30 compressions to 2 ventilations (n = 11,058).

Among patients with available data, the primary endpoint of survival until discharge was similar between the 2 CPR groups. Patients receiving continuous compression also were no more likely than those with interruptions to survive and be discharged with favorable neurological function (modified Rankin Scale score ≤ 3; table 1).

Additionally, patients assigned to continuous compressions were less likely to be transported to the hospital or to be admitted. Hospital-free survival—the number of days alive and permanently out of the hospital during the first 30 days after the cardiac arrest—was a mean of 0.2 days shorter for the continuous group (P = .004).

Prespecified per-protocol analysis capturing strict adherence to the treatment strategy showed lower survival with continuous compared with interrupted compressions (7.6% vs 9.6%; P < .001).

Undermining the Guidelines

Earlier research has shown a protective effect from continuous compressions, but “it seems plausible that some of the observed improvement in these previous studies was due to improved CPR process (eg, compression rate and depth), concurrent improvements in the system of care, or Hawthorne effects (changes in behavior resulting from awareness of being observed),” the researchers write.

Rudolph W. Koster, MD, PhD, of Academic Medical Center (Amsterdam, the Netherlands), notes that, based on positive observational data, the 2015 AHA resuscitation guidelines gave “a new class IIb recommendation that it may be reasonable for EMS to initiate resuscitation with 3 initial periods of 200 continuous chest compressions with passive oxygen insufflation.”

If the writing committee members had had access to the current study findings, they “might have decided to retain the previous recommendation to give chest compressions interrupted for ventilations and perhaps even to upgrade that recommendation to a class IIa recommendation for EMS providers,” Koster suggests. “Should the AHA reconsider their recommendation?”

Sources: 
1. Nichol G, Leroux B, Wang H, et al. Trial of continuous or interrupted chest compressions during CPR. N Engl J Med. 2015;Epub ahead of print.
2. Koster RW. Continuous or interrupted chest compressions for cardiac arrest [editorial]. N Engl J Med. 2015;Epub ahead of print.

Related Stories:

• Chest Compression Alone Does the Job for Bystander CPR
• Prognosis Poor for Primary PCI Patients with Cardiac Arrest Before Ambulance Arrival